FLOCCULATION OF BACTERIA BY HYDROPHILIC COLLOIDS

Abstract
Several naturally occurring and modified hydrophilic colloids, at 0.1 to 0.4% concentrations, flocculate cells of Pasteurella tularensis, Escherichia freundii, Serratia marcescens. and Proteus morganii, (and 7 additional species) from culture media at pH 7. The most effective flocculants are methylcellulose, carboxymethylcellulose, propyleneglycol alginate, and pectin. A ten to forty-fold concentration of cells is achieved with over 90% of the cells in the precipitate. Hydration of the colloids is essential. Flocculating properties of these materials are negated by enzymatic digestion or in some cases by heat treatment.